Terminal cap for spark plugs



Sept. 22, 1936. l.. F. HAHN i. 2,055,408

TERMINAL CA-F FOR SPARK PLUGS Filed June 9, v1932 INVENTOR LW S FRAN HUN HAH N provide an improved' terminal cap construction` Patented Sept. 11936 UNITED STATES PATENT OFFICE.

31 Claims.

The present invention relates to spark plugs for internal combustion engines and embodies, more speciilcally, an improved terminal cap construction for spark plugs. More specically, the invention embodies a terminal cap which is adapted for use in connection with shielded spark plugs for the type shown and described in my copending application Serial No. 396,950 led October 3, 1929.

The subjecty matter of this disclosure was copied from application Serial No. 509,919 tiled January 20, 1931, and became involved in interference No. 69,307, Hahn vs. Hahn and Grant. This interference terminated in an award oi priority in favor of the sole party, the applicant herein, in decision of examiner of interferences dated May 18, 1936.

In the use of shielded spark plugs of the above type and of other types now available, it has been found that the cover of the ignition cable is frequently softened due to the heat developed in the spark plug in operating conditions. The extent of such softening being suilcient to cause the covering to adhere to the insulation which separates it from the shield of the spark plug, thus makinar it extremely difllcult to separate the cable from the plug without injuring both the insulation of the cable and the plug insulation between the rst insulation and the shield. Furthermore, in connecting and disconnecting the cable `from the plugs of existing designs, it has been necessary to disconnect the ignition cable and its'metallic covering from the terminal cap of such plugs.

'There it is necessary to inspect or remove spark plugs frequently, this operation is slow .and rather` diicult to perform eectively and it is within the contemplation of the present invention to provide a terminal cap construction for shielded spark plugs by means of which the foregoing disadvantages are overcome.

An object of the invention, accordingly, is to for shielded spark plugs by means of which the ignition cable may be effectively connected and disconnected from the spark plugs to facilitate the inspection and removal of the plugs.

A further object of the invention is to provide a terminal cap construction which is adapted to be secured initially to the ignition cable and which il readily and effectively secured to the (Cl. 12S-169) spark plug in such fashion as -to permit the cap above character wherein means is embodied for effectively connecting the cap to the ignition cable.

A further object of the invention is to provide in combination with a shielded spark plug, a terminal cap construction and means for securing an ignition cable thereto, wherein' an auxiliary insulating sleeve is provided which may be readily removed from the plug when the cable and cap is removed, whereby adhesion of the cable to the plug is prevented.

Further objects, not specifically enumerated above, will be apparent as the invention is described in greater detail in connection with the accompanying drawing, wherein:

Figure 1 is a. view in section, showing a `ihielded spark plug and terminal-capl constructed in accordance .with the present invention.

Figure 2 is a. view in side elevation, showing a terminal cap constructed in' accordance with the present invention.

Figure 3 is a view in section, taken on line 3 3 of Flgure2, and looking in the direction of the arrows.

Referring to the above drawing, a shielded spark plug is shown comprising a tubular shell d provided at its lower end with an annular electrode b and provided externally withthreads c and is secured in place by a nut e threaded intothe upper end of the shell. The jacket 9 projects above the shell and nut and is 'provided at its upper end with threads ,f adaptedto be engeged by a coupling nut 4. I'he plug is provided with a terminal cap consisting of a sleeve l providedv with a. bare n adapted to have an eiectric lead I8 extendtherethrough and the lower end is engaged by a rolled over portion 3 of the cous1 pling nut. The upper' portion of lthe sleeveisA are preferably formed with grooves@ which, for

convenience of manufacture, may heproduced by a threading tool. These grooves enable the A :uns to gripthe 'ignition cable more eectively.

' The turned .b' l:

The coupling nut is provided with threads' e which engage the cooperating threads f on the jacket il', as clearly shown irl-Figure -l.- l

In orderlthat adhesion oi covering of the ignition cable to the spark plug may be prevented an insulating sleeve l@ is provided, in the speclnc form shown, this insulating sleeve being carried.l

The sleeve"I l@ is preferably by the sleeve l. formed of'lava or other suitabieheatresistant dielectric material andjis provided iwith an on larged-end portion il which'i'crins a shoulderis and at its upper end abuts against a shoulder 2i formed in the sleeve i. A portion oi' the metal of theiiange' 2 may be rolled ov'er the: shoulder :is as indicated at i2' to secure the sleeve' i@ eectivelv to' the cap. Although the construction is desc as mounting the ysleeve lo upon'the cap: it will be understood that this sleeve may constitute an lndependent element' which' A is.- loosely mounted within the' cap and plug. The length oi the sleeve l ois preferably sucient to entend vvithinsthe in f sulation l@ oi the jacket to a point adjacent the4 end le ci. the sparkfplug spindle to: The'internel dieteroithe insula ing sleeve-i@ is preerabw not lesstllan the' di eter of the liorefilV clothe sleeve member l, 'in'.order that no diculty may be encounteredin inserting the ignition vcsal'llo through the tingsleeve. Ilhe nut ispreferably Vior'nied with a skirt or-boredf out portion A it-to-'conceal-the threads f of the keine and improve'the appearancezthereoi. .In fi the cable'or otherelectric' lend i8 toithecan'the ine-i l ns oi. the sleeve andthe clarion?A is tightened. to

cause 'or teeth Iwithin thens tc; erin A i' portion jof thercelele;*enectively.v

the turned if The tightening ci: the .clelnp vin; itsxe gement with the misto-conical waistporuon es' or sleeve s; not ox'iliv secures the metalliccoverlng ehectlve to the 4tins but securely' grips the isnitioxrcolele 2li thereofsreheld Aly in itselfsothat- .l contact' with theterminalf-point at e upper end oiftheepindlefiti, i

se noted above, me menons nestelt seele not' be secured `.to the-'sleeve l but may ctionjustas effectively if it is insertedwithin thesparh-v plug loosely. the-insulating sleeve need not extend-within`sleeve -I` hutiit` isclent that the length thereoteextends from a `point ad@` jacent the spindle' i5 yto ra. point adjacent the sleeve l so' thetihere is noflzvossilillityoiv adhesion between the insulatiomoi `tlie isnitionfcable and the spark plus; Adhesion o f-theinsuletiomoi' the ignition cable to the insulating sleeve iis not detriine'ntaL'since the sieevefl will not adhere-to the'spark plug but may bewithdrawn whenever desirable. 'Ih'espindle l5 is provided atitslower end with a Acoasting electrodci 'andlbetwn the saine and the ilanse 'd is' disposeda'mica dislx form of insulation -1 for gjlie'at transference to'the spindle' l5 and metallic Jacket An insulating extensionk inthe'Iorxn'oi' a'tubula'r shell l acentos or whlch'sleeve n provides with e sense e which' fsieevemtstably.

ff' 3- A ceo for scorie clues es s sleeve adapted toreeeive an ignition cable, means to seeur' e the agsinstthe shoulder.

I 5.? A capfor snarhplugs having a sleeve adapted f to receive an ignition cable, me sleeve a restricted portion the top of the spindle lo; the upper portion being contained within the lower gartof the 1; tion i8 and forming in effect a continimticn of the lnsulsting sleeve iti.

It will thus be seen that a te o il; can bem provided for shielded sperir plugs which greatly facilitates the connection oi tion cables there, to and which i rl -:.f ore prevents adhesion between the cable and the plus. By seo the cable initially to the te :u fw. con, the connection of the cable to the plus is greatly facilitated since the csp may be readily secured. to plus and removed therefrom to permit inspection and removal ofthe pines. Theelente of the can are simple oi construction end re manufactured and aord a simple end eective m for secur- `:intr the cable to the cap, prior to the u; .1

the canto" the pli@- While the invention been deecri with specific reference to the accom if; nrawing,

it will be epperent'lthat' it is nda vice, and it is not to be ted', save as dened in curethe nrst sleeve to a cylindrical elent of a 1 spark plug, said flange fo u which the spark plus' element see when the capisscureflthere7 i 2. A cap for spark nhovin e sleeve soient ed to receive an ignition cable, i'ormed'vvith s hereto-:r:

a restcteol portion 'anda shoulden'm 'tosecure the tion cable to the sleeve, means for the sleeve toe. cylindrical elment of a snerrnlue end'rneans mounting the les@ r 'if isnition'- cablato the sleeve to project below the sleeve end intov the'snerh plus, means for secon ingthe'sleeve'to a cv :o ri element ci e snol-k plus, d a 'p =r.= tive sleeve carried liv the can antifspaced between' the spark plus end the por, tion' of the ii'on cable helow'the si.

,.- 4.: A can for speri; pl having a sleeve scented Ato "receive an ignition cable. "sleeve being formed with sabor-e ic a restric portionll and schouwen-.means to secure'the tion'cable to thesi'eeve", m for sec the sleeve to a. zcylindricel'eleinent of a rgk plumo'nd @time tfective sleeve carried hvlthe oep and seated cylindrical .element-oi a Spark pluma protective sleeve carried'by the can and seated against the n oulder Meinstsecuring means upon the the sleeve being shoulder, and `me to .secure protective sleeve against the shoulder.

' 6. A cap` for V,spark plugshaving a sleeve' adapted ,to receiveen ignition cable, the sleeve being -tormedwith e. bcretorming a restricted l, l

portion and: a shoulder, means to secure'the v' ignition cable to the sleeve,means for securing the .e to s cylindrical element ofl s slm-kV plug, a protective sleeve carried by the cap and seated against the shoulder, and a turned over portion on the bore engaging the protective sleeve to secure the same against the shoulder.

7. A cap for spark plugs having a sleeve adapted to receive an ignition cable, the sleeve being formed with a bore forming a restricted portion and a shoulder, means .to secure the ignition cable to the sleeve, means for securing the sleeve to a cylindrical element ofl a spark plug, a protective sleeve carriedV by the ca p and .seated against the shoulder, an enlarged shouldered end on the protective sleeve, and a turned over portion on the bore engagingthe enlarged shouldered portion ot the protective sleeve to secure vthe same against the shoulder.

8. A cap for spark plugs having a sleeve adapted to receive an ignition cable, means to secure theignition cable to the sleeve, and a threaded sleeve rotatably mounted on the sleeve freely to secure the sleeve `to a cylindrical elef ment of a spark plug.

9, A cap for spark plugs having a sleeve adapted to receive an ignition cable, means to secure the ignition cableto the sleeve, means for securing the sleeve to a cylindrical element of a spark plug, and a protective sleeve carried by the cap, the' bore of the protective sleeve befing at least as great as that of the iirst sleeve.

10. A cap for spark v,plugs having a sleeve y.

adapted to-receive an ignition cable, means to I secure the ignition cable to the sleeve', means for securing the sleeve to a cylindrical element of a spark plug, and a protective sleeve carried rotatably by the cap.

l1. A connecting cap having a 'sleeve adapted to receive an ignition cablemeans to .secure .the ignition cable to the sleeve, 'means for securing the sleeve to an electrical device', and means mounting the last named securing :means axially fixed but freely rotatable upon thev sleeve.

12. In a spark plug, the combination of a .tubular metallic Jacket of nigh heat conducting@- .fpacity, a spindle in the jacket, proiectingtherefrom and provided at its lower 'end' with an electrode, insulating means between the'electrode and the adjacent end of the jacket. be-

y tween the spindle and jacket and extending to the top of the spindle and still other insulation 50 the intruded electric lead. an insulating sleeve surrounding the upper portion of the spindle, a second insulatingsleeve containedin the upper portion of the jacket encircling the first named insulating sleeve and projecting above and below the upper Vend of the spindle, anda third insulatlng sleeve positioned vabove and constituting in eifect a continuation of the rst named sleeve separable therefrom and substantially containedy within the outlines of the second'named sleeve. i4. In a spark'plug, the combination or an air cooled open top metal'jacket, a spindle extendin .axially of the jacket and providedat its' end with means within the outlines of the'fiacket for connection with an electric lead. insulating means surrounding and engaging the spindle, other insulating means lining the upper portion of the jacket bore, extending above/the upper end of the spindle and adaptedv to enclose the intruded end of the electric lead, and an electric lead provided at its intruded end with a sleeve secured thereto and forming a third insulation positioned for the most part -in the jacket above the spindle and adapted to position insulation between the intruded end o i' the electric lead and the insulating meanswhichines the jacket and a metallic member for securing said sleeve to the jacket.

l5. A connecting cap comprising a sleeve having a bore adapted to receive an ignition cable,

means at one end of the-.sleeve to secure thel same to an electrical device,'the other end of said sleeve having its outer surface iiarin'g outwardly to a maximum diameter from a section of minimum diameter; and a clamp engaging `the external ilaring surface over an extended area axially thereof. I

16. A connecting cap for spark plugs, comprising a sleeve having a bore adapted to receive an ignition cable, means to secure'the ignitioncable tothe sleeve, means for securing the sleeve to an electrical device, and, means mounting the last named securing-means upon the sleeve in an rotatably. I

1,8. In a spark plug, the combination of a shell provided with an electrode) a unit including a spindle constituting an insulated coacting electrode and a barrel extending above the spindle to l form a socket, an insulatedelectric lead having a i ilexible metal covering, a metal tubular member through which said conductor is passed and 'to the outer end of which said metal covering is electrically" connected, v the end .of the insulated lead being inserted in saidfsocket to make electrical connection with the spindle, and a terminal on the inner end of said tubular member, locking detachably with said barreiand forming a swivel connection between the tubular member and the barrel. e

19. In a spark plug having a shell and a central spindle insulated from the shell, the combinationof a metal barrel with-insulation lining extending upward from the shellmbove the upper end of the spindle to provides. socket for the insertion of an insulated lead into electric connection with said spindle, a; connection through which the lead is passed and which has detachable connection with said barrel and an insulating tube about the portion of the insulated lead within said socket. said tube being -connected to the lead and arranged to engage at its upper end with said connection.

20. A spark plug including a supporting tubuwhich thev conductor :s psss'ed and nld sleeve provided at its lower end withv a' ange and a coupling nut engaging said threaded end of the jacket, and provided with an internal upper end overlapping the flange on the sleeve.'

2l. A spark plug including a supporting tubular shell provided with an electrode, a long upstanding tubular metallic jacket having its lower end demountably positioned in the shell and in electric engagement therewith, a coacting elec-y. trode centered axially in the jacket and insulated therefrom, said jacket having its upper end open to provide a socket for the insertion therein of a. high tension lead, an insulating sleeve outlining said socket, a connecting sleeve extending above the jacket secured to the high tension lead and readily separable swivel means for securing said connecting sleeveto the upper end of the jacket.

22. Means for fastening a cable on a spark plug or theI like, comprising a metallic sleeve connected with said spark plug or the like, a nut screwed on the outer end oi said sleeve, a member fastened on said cable, said cable extending through the bore of said nut and engaged therewith, said nut and member provided with means actuated by the rotation of the nut on the sleeve and cooperating for fastening the cable to the sleeve.

23. Means for fastening an electric lead on a spark plug comprising a metallic sleeve having its upperend threaded, an'electric lead having a metallic covering, an end of said lead extending beyond its covering and intruded into saidl sleeve, a telescopic tubular swivel connection through which the lead extends with one tubular part secured to the lead and the other tubular part in threaded engagement with the threaded en d of the sleeve, and said connection including 9,055,408'L 26. A spark plug including a supporting shell provided with an electrode, along metallic sleeve with its lower end engaging in the shell and its upper end provided with an element of a fastening means, the bore of the sleeve being reduced adjacent its lower end, with its upper end open, a spindle extending axially through and projecting both above and below the reduced portion of the bore, the lower end of the spindle provided with a head forming the coacting electrode and having its upper end exposed to form a terminal, an insulating sleeve surrounding the spindle above the head, an insulating sleeve forming a lining to the portion of the bore above its reduced portion, an electric lead intruded into the upper end of the long metallic sleeve for electric engagement with said terminal, the lead provided with a metallic covering, coupling means engagat the bottom of the spindle and the lower portion extending beyond its covering and intruded into the bore oi said sleeve, a swivel connection including telescopic tubular parts with one part encircling and secured to the lead and the other tubular part being internally threaded and adapt-l ed to be disposed in threaded engagement with the threads on the sleeve, and said connection including clamping means for securing in place the adjacent end oi the metallic covering.

25. A spark plug including a supporting shell provided with an electrode, a long metallic sleeve with its lower end engaging in the shell and its upper end provided with threads forming an eleacting electrode and having its upper end exposed i to form a terminal, an insulating sleeve surrounding the spindle above the head, an insulating sleeve forming a'lining to the portion of the bore above its reduced portion, an electric lead intruded into the upper end oi the long metallic sleeve for electric engagement with said terminal, the lead provided with a metallic covering, and coupling means, a coupling nut engaging the adja- I- cent end of themetallic covering and having a readily releasable engagement with the threads forming the fastening meansat the upper end ci the metallic sleeve.

ing the adjacent end of the metallic covering and having a readily releasable screw threaded engagement with the fastening means at the upper end of the metallic sleeve, and additional insulating means between the electrode forming head of the metallic sleeve.

27. In a spark plug, the combination of a tubular metallic jacket open at its upper end and provided with insulating material lining the upper portion of its bore, a spindle extending axially of the jacket insulated'therefrom, having its upper end spaced below the open top of the jacket and having its lower end projecting below th jacket and provided at its lower end with an ectrode, a sleeve projecting above the open en'd oi the jacket, and adapted to have an electric lead extend therethrough and through the open end of the jacket for engagement with the upper en d o the spindle, and readily separable screw threaded means for detachably securing the sleeve to the upper end of the jacket.

28. A spark plug including a shell, a unit carried by the shell and comprising a tubular metalY Ajacket open at its upper end, a spindle having its upper end contained in the jacket below its upper open end and adapted to be connected to an electric lead, a sleeve having a bore adapted to receive the'electric lead and having apart split, a clamping device encircling the split end of the sleeve and a coupling nut connecting the sleeve and jacket.

29. In combination, a spark plug including an open top metallic sleeve forming a jacket, a protective sleeve of insulating material lining the upper portion oi the jacket, a third sleeve forming Ya cap positioned on top of the jacket and forming an upward continuation thereof, means Vfor securing the cap to the jacket, a fourth sleeve constituting a second protective sleeve oifinsulatlng material having its upper end secured to the cap, removable therewith, projecting `-downwardly therefrom and intruded into the upperA end of the rst named lining sleeve, and an electric lead passed through the cap and having its intruded end surrounded by both protective sleeves.

30. In a spark plug assembly, the combination with a spark plug provided with a socket and a spindle centered in said socket, of an electric lead adapted ltobe intruded into the socket to make electric connection with the spindle without rotating the lead relative to the spark plug when the attachment is made, said lead provided adjacent its intruded end with a two-part coupling with one part freely rotatable relative to the other when free oi' the spark plug, the part remote from the intruded end of the lead being secured to the electric lead and the other part provided with means for engaging the socket forming end oi' the spark plug thereby to secure the lead to the spark plug.

31. In a device of the class described; the combination of two readily separable parts, one of said parts comprising a spark plug and including an open top jacket and va. spindle in the jacket, and the other part comprising an electric lead having an end portion intruded into the open top of the jacket and electrically connected to the spindle, a metallic sleeve secured to the electric lead externally of its intruded end portion and movable therewith and an insulating sleeve telescopically engaging the intruded end portion of the lead and swivel means for securing the metallic sleeve to the jacket to connect the parts together without materially rotatingthe electric lead relative to the spark plug.

LEWIS FRANKLIN HAHN.

CERTIFICATE OT? CORRECTION.

Patent No. 2,055,408. September 22,' 1936.

LEWIS FRANKLIN HAHN.

It is hereby certified that ,error appears in the printed specification of the above numbered patent requiring correction as follows: Page 2, second column, linee 30 and 3l, claim l, strike out the words andcomme. "and e. second sleeve engaging the flange on the sleeve, and that. the said. Lettere 1 Patent should be read with this correction therein that the same may 'conform to the, record of the case in the Patent Office.

Signed and Sealed this 22nd day of December A. D. 1936.

Henry Van Arsdele (Seal) Acting Commissioner 4of Patents.

DISCLAIMER 2,055,408.Lewz's Franklin Hahn, New York, N. Y. TmmAL CAJ? FOR Smm: PLUGS. Patent dated September 22, 1936. Disclaimer filed July 18,1941, by the assignee, Att-Shields Incorporated.

Hereby enters this disclaimer to claims 3, 5, 9, 12, 14, 18, 19, 21,1a1d 31 of said Letters Patent.

[Oficial Gazette August 12, 1.941.] 

